Inboard motor boat

ABSTRACT

An inboard motorboat having, located in the rear half of the bottom of the boat and extending to the stern longitudinally, an upwardly recessed water passageway, an engine detachably provided on the inside of the boat at the upper wall of said waterpassageway, said engine having a screw propeller coupled thereto, said screw propeller protruding into said water-passageway, whereby accommodating said propeller within the bottom contour of the hull without protruding beyond this bottom.

United States Patent -191 Kobayashi et a1.

[451 May 21, 1974 INBOARD MOTOR BOAT [75] Inventors: Torao Kobayashi; Hisashi Inaga,

Loetzer....

Harvey 1 15/41 3,213,822, 3/1964 Sawchuk 115/70 3,469,557 9/1969- Wollard 115/39 Primary Examiner-Robert G. Sheridan Assistant Examiner-Gary Anton Attorney, Agent, or Firm-Karl W. Flocks [5 7] ABSTRACT An inboard motorboat having, located in the rear. half of the bottom of the boat and extending to the stern longitudinally, an upwardly recessed water passageway, an engine detachably provided on the inside of the boat at the upper wall of said water-passageway, said engine having a screw propeller coupled thereto, said screw propeller vprotruding into said waterpassageway, whereby accommodating said propeller within the bottom contour of the hull without protruding beyond this bottom.

1 Claim, 7 Drawing Figures FATENTEDIAY 21 I974 sum 1 0r 3 FIG FIG, 2

F'ATENTEDMAY 2 1 1914 SHEET 2 BF 3 w LY%\\IIII I FATENTEMAY 21 1914 3.81 l 399 sum 3 or a FIG.6

FIG.7

INBOARD MOTOR BOAT BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention pertains to motorboat, and more particularly it relates to a motorboat of the socalled inboard engine type having an engine and a propeller mounted inside the boat but being arranged so that the engine and the propeller can be easily mounted and removed as in the case of the outboard motorboat, and in addition thereto, this boat of the present invention is of an improved cruising ability and stability and also an increased safety.

2. Description of the Prior Art Among those boats propelled by a compact size prime motor, the one which is called in general the outboard motorboat has, at its stern, an integral driving unit which is comprised of an engine and a propeller, and is propelled by this driving unit. The propeller of such a known outboard motorboat, however, protrudes beyond the bottom of the boat. This makes it impossible for the boat to cruise on a shallow water, and also gives much inconvenience for the user in handling or transporting the. boat. Moreover, such a protruding propeller gives rise to the danger that its screw contacts things or swimming persons.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to eliminate the drawbacks ofthe prior art and to provide an inboard motorboat having, located in the rear half of the bottom of the boat and extending to the stern longitudinally, an upwardly recessed waterpassageway, an engine detachably provided on the inside of the boat at the upper wall of said waterpassageway, said engine having a screw-propeller coupled thereto to form an integral drive unit, said screwpropeller protruding into said water-passageway, whereby accommodating said propeller within the bottom contour of the hull without protruding beyond this bottom.

As a consequence, the safety during cruising and the easiness in handling the boat increase greatly.

Another object of the present invention is to provide an inboard motorboat having, located in the rear half of the bottom of the boat and extending to the stern longitudinally, an upwardly recessed waterpassageway, an opening provided through the top wall of said water-passageway, an engine-mounting seat projecting upwardly beyond said top wall of the waterpassageway from the peripheral edge of said opening and having a flat upper end surface, and an engine having a propeller coupled thereto and being detachably mounted on said seat, said propeller protruding into said water-passageway, said propeller being accommodated within' said'water-passageway without any parts thereof projecting beyond the bottom contour of the hull of the boat.

The inboard motorboat according to the present invention is arranged as stated above. Therefore, it is possible to accommodate both the engine and the screwpropeller within the water-passageway formed at the bottom of the boat or in other words within the bottom contour of the boat, and it is also possible to mount and remove them with such an easiness as is substantially equal to that for a known outboard motorboat.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat diagrammatic side elevation, partly broken away, of the motorboat according to an embodiment of the present invention.

FIG. 2 is a somewhat diagrammatic bottom view of the boat shown in FIG. 1.

FIG. 3 is a somewhat diagrammatic rear view of the boat shown in FIG. 1.

FIG. 4 is a somewhat diagrammatic sectional view taken along the line A-A in FIG. 1.

FIG. 5 is a longitudinal sectional view showing the details of the engine and the propeller.

FIG. 6 is a somewhat diagrammatic side elevation, partly broken away, of the motorboat representing another embodiment of the invention.

FIG. 7 is a somewhat diagrammatic bottom view of the boat shown in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Description will be made .more concretelyon a couple 'of embodiments of the present invention by referring to the accompanying drawings which are given by way of example.

A boat 1 has a hull 2 and a deck 3. This hull 2 has a flat bottom 4 of the boat 1. In the rear half of this bottom' 4 of the boat 1 is formed an upwardly recessed open chamber 5, that is to say this open chamber 5 is concave into the body of the boat 1. This open chamber 5 is of a substantially semi-circular vertical section which has an almost constant breadth between the opposing edges of the opening. More specifically, the opposing side walls of this open chamber 5 extend in parallel relative to each other. This open chamber 5 has depths such that its depth increases progressively at the inclined portion 14 towards the stern of the boat 1 and that, in the vicinity of the stern, the depth is kept almost constant, and also that the chamber 5 opens towards the rear side of the boat from the stem with the same depth as that at the stern.

In the upper wall of the open chamber 5 is formed an opening 6 for the insertion of an engine-propeller assembly. A projecting brace 7 extends upwardly from the entire edge of the opening 6. The upper end of this projecting brace 7 has a flat surface to provide a seat for mounting an engine thereon. A steering. shaft 8 is arranged between said opening 6 and the stern. A rudder 9 is arranged to lie within said open chamber 5. It should be understood that this open chamber 5 serves as the passageway for the water currents which are produced during the cruising of the boat 1. Therefore, it

is to be understood that the terms open chamber is used as a synonym of the terms water-passageway in the following statement.

An engine E is fastened, via an appropriate buffer member 13, onto said mounting seat. In doing so, a propeller 10 is arranged so that it will be received within the water-passageways 5 and will not protrude outwardly from the contour of the boat 1.

By the provision of the opening 6 in the upper wall of the water-passageway 5, the configuration of this watear-passageway 5 is interrupted at the site of this opening 6. This interruption of the configuration of the water-passageway 5, however, can be prevented by forming that frame or casing portion 12 of the lower part of the engine body which is located in the waterpassageway 5 so as to assume the vertical sectional configuration of the water-passageway 5. By thus preventing the interruption of the water-passageway, it is possipresent invention,'the engine and the propeller are provided as a compact integral unit, and moreover the propeller per se is accommodated completely within the water-passageway provided at the bottom of the boat without protruding outwardly beyond the contour of the boat. Accordingly, it is possible to prevent the occurrence of an unexpected accident such that the rotating screw contacts a floating object or a swimming person during cruising. Also, the engine as well as the propeller can be mounted onto the boat and removed therefrom in substantially the same manner and easiness as for the outboard motorboat. Furthermore, the arrangement of the propeller accommodated within the contour of the bottom of the boat makes it easy to transport and handle'this motorboat of the present invention, so that it is also possible to perform test operation of the machine on land.

FIGS. 6 and 7 show another embodiment of the motorboat according to the present invention. in this embodiment, the steering shaft 8 and the rudder 9 protrude backwardly from the stern of the boat 1. Other parts and arrangement of the boat 1 are substantially the same as thoseof the boat shown in FIGS. 1 and 2.

FIG. 5 shows a changeover means structure for reversing' the direction of rotation of the propeller from forward to backward and vice versa, which is suitable for use in the propeller of the motorboat of the present invention.

At the end of the extension of a rotary shaft 20 of the engine is provided a bevel gear 21. On a propeller shaft 22 which crosses said rotary shaft 20 at right angle are provided bevel gears 23 and 24 which sandwich and mesh with said bevel gear 21. These two bevel gears 23 and 24 are rotatably'and loosely mounted on the propeller shaft 22. A spline is formed on that surface of the propeller shaft 22'located between the two bevel gears 23 and 24. A clutch 25 is spline-received in this spline for axial sliding movement. This clutch 25 is provided v with pawls 26 and 26' at its opposite end faces in such a way that'these pawls may mesh with either one of the engaging pawals 27 and 28 of thebevel gears-23 and 24. Accordingly, the rotation of the bevel gear 21 is transmitted to the clutch 25 via either one of the bevel gears 23 and 24. The resulting rotation of this clutch 25, in turn, is transmitted to the propeller shaft 22 via said spline-received mechanism. The bevelgears 23 and 24 rotate in the opposite directions relative to each other on the propeller shaft 22. Accordingly, by bringing the clutch 25 into mesh with either one of the bevel gears 23 and 24, it is possible to selectively determine the direction of rotation of the propeller shaft 22.

lt should be understood that the clutch 25 is arranged so as to be able to assume an intermediate or neutral position in which the clutch 25 is not brought into mesh with either one of these two bevel gears 23 and 24, whereby the rotation force is not transmitted to the propeller shaft 22. A propelling screw 29 is secured to one end of the propeller shaft 22.

The clutch 25 is provided with an actuator plug 30 which traverses the propeller shaft 22 through an opening formed therein. The amount of axial movement of the clutch is determined by the amount of the gap existing between said traversing opening of the propeller shaft 22 and said actuator plug 30. in the propeller shaft 22 are formed two hollow portions, one of which is located in the region before said actuator plug 30 and the other in the region behind this plug 30. A repelling spring 31 is inserted in one of these two hollow portions to normally urge the actuator plug 30 in one direction.

Also, a pressing member 32 is inserted in the other hollow portion to serve as the member to exert a counteracting force against the urging force of the spring 31 at one end of this member 32. A slidable member 33 having an inclined end surface is arranged at the other end of this pressing member 32 so as tobe in contact with said the other end of the pressing member 32 to control the position assumed by the pressing member 32. This member 33 having an inclined end surface is able to slide in the direction perpendicular to the pressing member 32, and is operated remotely by a coupling rod 34 or like means.

The mechanism shown in F l6. 5 represents the state as viewed in the drawing. As a consequence, the rotating bevel gear 23 and the clutch 25 approach towards each other so that the pawl 26 of the clutch 25 is brought into mesh with the engaging pawl 27 of the bevel gear 23 and that, accordingly, the'rotation of thebevel gear 23 is transmitted to the and thus the screw 29 is rotated.

Conversely to the foregoing operation, by shifting downwardly the slidable member 33 having an inclined end surface, the clutch 25 moves in the direction opposite to that stated previously, and via the intermediate or the neutral position, the clutch 25 is changed over to its position for reverse rotation of the shaft 22.

Such a means for reversing the direction 'of rotation of the propeller shaft 22 is housed. in a stream-lined frame formed at the lower portion of-the engine body frame, and is assembled as an integral unit of the engine body.

We claim: 1. An inboard motorboat having, located in the rear half of the bottom of a hull of the boatand extending to the stern longitudinally, an upwardly recessed waterpassageway, an opening provided through the top wall of said water-passageway, an engine-mounting seat projecting upwardly beyond said top wall of the waterpassageway from the peripheral edge of said opening and having a flat upper end surface, and an engine having a propeller coupled thereto and being detachably mounted on said seat, said propeller being arranged in said water-passageway and connected to said engine by means of a driving rotary shaft vertically extending propeller shaft 22,

through said opening, said propeller being accommoseat being provided with a lower end face which has a dated within said water-passageway without any parts configuration substantially in conformity with the secthereof projecting beyond the bottom contour of the tional configuration of the upper wall 'of said waterhull of the boat, and the lower portion of the frame of passageway.

said engine located lower than said engine-mounting 

1. An inboard motorboat having, located in the rear half of the bottom of a hull of the boat and extending to the stern longitudinally, an upwardly recessed water-passageway, an opening provided through the top wall of said water-passageway, an engine-mounting seat projecting upwardly beyond said top wall of the water-passageway from the peripheral edge of said opening and having a flat upper end surface, and an engine having a propeller coupled thereto and being detachably mounted on said seat, said propeller being arranged in said water-passageway and connected to said engine by means of a driving rotary shaft vertically extending through said opening, said propeller being accommodated within said water-passageway without any parts thereof projecting beyond the bottom contour of the hull of the boat, and the lower portion of the frame of said engine located lower than said engine-mounting seat being provided with a lower end face which has a configuration substantially in conformity with the sectional configuration of the upper wall of said waterpassageway. 